The present invention relates in general to ski boots and has specific reference to ski boot of the type comprising at least two portions with overlapping edges for surrounding the foot or ankle of the skier, and at least one closing and tightening device for interconnecting these two portions, this device comprising a cogged or perforated strap or belt secured to one of said boot portions and adapted to cooperate with hooking and tightening means carried either by the same portion or by the other portion of the boot.